Liquid-liquid separation is a separation and purification process that involves mass transfer of biomolecules from a solvent to another immiscible solvent that exhibits preferential selectivity toward the biomolecules from the feedstock. A partitioning effect is created between the two liquid phases during formation of a two-phase system. Liquid-liquid separation represents an important bioseparation tool for biomolecule recovery, such as lipase, lipids, enzymes, antibiotics, and proteins. Conventional liquid-liquid separation possesses disadvantages, such as high operation cost, low yield and purity, high chemical consumption, and environmental hazards; as a consequence, progressive technologies are introduced to mitigate these drawbacks. Three different techniques of liquid-liquid separation (conventional liquid-liquid separation, liquid biphasic partitioning system, and liquid biphasic flotation system) are discussed in Chapter 8. In comparing all three technologies, liquid biphasic flotation system has an impressive separation efficiency and higher molecule recovery yields and can be employed in industries for purification of biomolecules.